Uno is a fun to play card based game. The deck consists of cards of four colors: red, green, blue, and yellow. The ranks in each color are 0-9. There are three "action" cards in each color, labeled "skip", "draw two", and "reverse". There are also special black action cards, "wild" and "wild draw four".

There are two copies of each colored regular and action card, except for the zero card, which only have one per suit. There are four "wild" and "wild draw four" cards each, producing a total of 108 cards.

In older versions, only the 6 is underlined to distinguish it from the 9, which is not marked; newer versions have both the 6 and the 9 underlined to further distinguish the two ranks.